The subject matter disclosed herein relates to a heating and ventilation inlay for a vehicle seat, which heating and ventilation inlay is adapted to be placed in a complementary recess in a seat cushion or backrest of the vehicle seat to be disposed underneath a seat trim, wherein the heating and ventilation inlay comprises an arrangement of layers including an air permeable heating mat having a heating conductor running on the heating mat, and underneath the heating mat an air permeable layer of spacer material which is connectable to a fan or suction fan for transporting air conveyed by the fan or suction fan through the area of the heating and ventilation inlay.
Such a heating and ventilation inlay is known from WO 2014/058429 A1 which describes a vehicle seat having as usual a seat cushion and a backrest connected thereto. For reasons of comfort the vehicle seat is provided with a seat heating and with a ventilation arrangement by which air transported by a fan or suction fan is transported through the seat trim. For this purpose the cushion material of the seat body is provided with a recess in the seating area, in which recess a heating and ventilation inlay can be placed. The recess has a contour which is complementary to the outer contour of the heating and ventilation inlay. The heating and ventilation inlay has a lower, air permeable layer of spacer fabric, on top of which a heating mat is disposed which is in contact with an inner surface of a seat trim. A conduit extends through the cushion material of the seat body from below into the recess, which conduit is in communication with a fan or a suction fan. In the following, for simplifying formulations, reference is made to a fan, wherein this is intended to also include a reversely operating suction fan. During operation of the fan air is conveyed through the conduit into the recess, which air is distributed by the air permeable layer of spacer fabric and which continues to flow through the heating mat and the seat trim.
Spacer fabrics or spacer nettings are three-dimensional textiles which in general comprise two cover layers which are connected by so-called pile yarns and which are held at a distance to each other. The spacer fabrics are knitted or woven fabrics which are extended to three-dimensions and which have a high air permeability due to the interstices between the filaments or yarns. The function of the air permeable spacer fabric layer is to keep open flow paths over the entire area of the spacer fabric layer such that air transported by the fan (or suction fan) may be distributed over the area of the spacer fabric layer, even if a passenger is seated on the vehicle seat and the weight of the passenger weighs on the spacer fabric layer. Spacer fabrics are also referred to as “spacer materials” or “mesh materials”. For the heating and ventilation inlay described in WO 2014/058429 A1 the spacer fabric layer is referred to as a honeycomb support structure.
Above the air permeable spacer fabric layer an air permeable heating mat is disposed. Between the spacer fabric layer and the heating mat an air permeable cushion layer can be placed so that a passenger sitting on the vehicle seat does not feel the spacer fabric layer through the thin heating mat. The heating mat comprises for example a carrier layer of fleece, felt or woven material, on which carrier layer a heating conductor is laid; the heating conductor can be laid on the carrier layer running back and forth, in a meander pattern or with several parallel conductors. The heating conductor can be connected to a direct current source. The current supply to the heating conductor and the operation of the fan or suction fan are controlled by control units which may be connected to manual input elements for adjusting heating and ventilation.
Also the backrest has in its base body a recess in the cushion material facing the back of a passenger when seated, in which recess a heating and ventilation inlay is placed and connected before the seat trim is applied. In the vehicle seat described the spacer fabric layers and the heating mats are separate components which are mounted one after the other.
It has already been recognized that it would be desirable to integrate the heating mat and the air permeable spacer fabric layer required for ventilation already in advance during manufacturing to a united assembly or unit which is then shipped as a unit and mounted in the vehicle seat as a unit. Such an integrated heating and ventilation inlay is disclosed in U.S. Pat. No. 6,869,140 B2. The heating and ventilation inlay comprises an air permeable spacer fabric layer and lying on top of that an electrical heating mat. For integration these are enclosed in a bag of air impermeable material, which bag enwraps the heating and ventilation inlay. The bag is connected to a conduit connectable to a fan, and is, in the surface area which after mounting in the vehicle seat is in contact with the seat trim, provided with a plurality of holes. During operation of the fan, depending on the operation mode regarding the pumping direction as a fan or suction fan, air is forced into the air impermeable bag or is drawn from the bag which results in an air flow through the holes on the top surface of the bag and through the seat trim disposed on top of the bag. Since there are only individual, distributed holes in the upper surface of the bag, the flow resistance which is created by this heating and ventilation inlay is rather high, i.e. a fan having high capacity or performance is needed in order to be able to pump a sufficient amount of air through the heating and ventilation inlay.